At present, the linkage of handling equipment, of road vehicles or the like, namely the linkage between the various foldable elements of a crane boom, the linkage of the outriggers of certain road vehicles and/or their trailers or semi-trailers or the like, or also the linkage of a swinging yoke for a bucket or the like, or all other mechanisms requiring rotative or rectilinear movement, are generally effected by means of jacks disposed between the elements constituting the linkage, by mounting under or on said elements.
Such an embodiment imposes very great force on said elements and requires a large size of the assembly thus provided.
It has been proposed to overcome this drawback by placing the jack partially within at least one element of the linkage, which however gives rise to the need to reinforce the side walls of the casing forming said element.
Moreover, such an arrangement of a jack on the upper or lower surface of at least one of the linkage elements also has the drawback of exposing said jack to the risk of rapid deterioration, by shock or by pressure on or against foreign bodies, requiring its frequent replacement and therefore high maintenance costs.
Finally, the jacks utilized in these types of linkages generally require, even though disposed within the linkage, a very large size.